Write C code to dynamically allocate one, two and three dimensional arrays (using malloc()).

Its pretty simple to do this in the C language if you know how to use C pointers. Here are some example C code snipptes....

One dimensional array

int *myarray = malloc(no_of_elements * sizeof(int));

//Access elements as myarray[i]




Two dimensional array

Method1


int **myarray = (int **)malloc(no_of_rows * sizeof(int *));
for(i = 0; i < no_of_rows; i++)
{
myarray[i] = malloc(no_of_columns * sizeof(int));
}

// Access elements as myarray[i][j]



Method2 (keep the array's contents contiguous)


int **myarray = (int **)malloc(no_of_rows * sizeof(int *));
myarray[0] = malloc(no_of_rows * no_of_columns * sizeof(int));

for(i = 1; i < no_of_rows; i++)
myarray[i] = myarray[0] + (i * no_of_columns);

// Access elements as myarray[i][j]


Method3


int *myarray = malloc(no_of_rows * no_of_columns * sizeof(int));

// Access elements using myarray[i * no_of_columns + j].



Three dimensional array

#define MAXX 3
#define MAXY 4
#define MAXZ 5

main()
{
int ***p,i,j;
p=(int ***) malloc(MAXX * sizeof(int ***));

for(i=0;i < MAXX;i++)
{
p[i]=(int **)malloc(MAXY * sizeof(int *));
for(j=0;j < MAXY;j++)
p[i][j]=(int *)malloc(MAXZ * sizeof(int));
}

for(k=0;k < MAXZ;k++)
for(i=0;i < MAXX;i++)
for(j=0;j < MAXY;j++)
p[i][j][k]= < something >;

}